Affected: Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP, Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP, Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP, Siemens RUGGEDCOM ROX MX5000, Siemens RUGGEDCOM ROX MX5000RE, Siemens RUGGEDCOM ROX RX1400, Siemens RUGGEDCOM ROX RX1500, Siemens RUGGEDCOM ROX RX1501, Siemens RUGGEDCOM ROX RX1510, Siemens RUGGEDCOM ROX RX1511 and 4 more

In Shadow 4.13, it is possible to inject control characters into fields provided to the SUID program chfn (change finger). Although it is not possible to exploit this directly (e.g., adding a new user fails because \n is in the block list), it is possible to misrepresent the /etc/passwd file when viewed. Use of \r manipulations and Unicode characters to work around blocking of the : character make it possible to give the impression that a new user has been added. In other words, an adversary may be able to convince a system administrator to take the system offline (an indirect, social-engineered denial of service) by demonstrating that "cat /etc/passwd" shows a rogue user account.